1. Field of the Invention
The present invention relates to image processing for preventing forgery of paper money, securities and the like.
2. Description of Prior Art
Recently, a peripheral of a computer such as a scanner or a color printer has improved functions and higher performance, and a possibility is increased that an average consumer can copy paper money, securities and the like easily. Then, effective countermeasures for preventing forgery have been developed. One of methods for preventing forgery is to include a specified pattern in a design of paper money or the like. The specified pattern is embedded in an image so as not to be noticed by a user in the standpoint of prevention of forgery. Image data is analyzed before printing, and when the specified pattern is detected in the image data, normal print operation is stopped.
When an image is printed based on input image data, the detection of the specified pattern is performed in parallel to the printing of the image. That is, while the input image data is subjected to predetermined image processing and is sent to the printer, the input image data is in parallel subjected to the detection of whether the specified pattern is included or not. When the specified pattern is detected, the transmission of image data to the printer is stopped, and the printing is interrupted. In this case, when the printing is interrupted according to the detection of the specified pattern, the printing of the entire image is prevented, but the printing is already started. Thus a part of the image has already been printed. Therefore, when the print operation is stopped by stopping the transmission of image data to the printer just when the specified pattern is detected, the printing is stopped just after the position of the specified pattern included in the image. Therefore, it is liable that the position of the specified pattern in the image may be estimated based on the stop potion of the printing. Therefore, this is not favorable for the prevention of forgery.